Blade testing apparatus



sept. 22, 1936. A I E p FLOYD 2,055,125

BLADE TEST ING APPARATUS Filed June 7, 1955 Patented Sept. 22, 1936 man BLADE` TESTING APPARATUS Ernest Paul Floyd, Fitchburg, Mass., assignor to Simonds Saw and Steel Company, Fitchburg, Mass., a corporation of Massachusetts Application June 7, 1935, Serial No. 25,421

Claims.

This invention relates to apparatus for determining the cutting ability of a blade or blades, and not only permits a quantitative determination of the keenness of a blade, but also permits the 5 determination of rate and extent of the deterioration thereof, as well as the comparison ofthe sharpness or the deterioration thereof of two or more blades.

To permit these desirable results, a sheet of material of known characteristics, such for example as paper of standardized character, may be pressed against a given portion of the edge of the blade with a determined pressure and then relative movement may be effected between the sheet and the blade in the 'direction of extent of the cutting edge, this movement being continued until the sheet of known characteristics has been severed. Thereupon the extent oi the movement is measured to afford an indication of the cutting ability of the blade.

In order to permit the convenient testing of a blade in this manner, I have devised a machine which includes a blade support arranged to hold a blade with its cutting edge uppermost and a weight guide disposed above and in parallel relation to the cutting edge of the blade mounted upon the support. A weight is associated with the guide so that normally it` rests not on the guide but on the cutting edge ofthe blade or on a sheet of material, such as paper, disposed over the cutting edge of the blade. The weight may be in the form of a block or supporting element shaped conveniently to slide along the guide and provided with means to receive various additional weight elements of known mass. Thus the total weight of the supportingelement and the element supported thereby maybe known'. The element itself provides a portion having a known dimension of constant size, which'rests on the blade or on a sheet of paper engaging the cutting edge of the blade. A'

rI "hus the paper may be forced against a known extent ofV the blade under a determined pressure. The sheet may then be grasped and pulled manually until it is severed, whereupon the weight rests upon the cutting edge of the blade, although the sheet may continue to move. 'Ihe weight guide may be provided with a graduated scale so that the length of the path of the weight is readily determined. A

Obviously when arsharp blade is employed, a relatively short movement of the paper and weight is required in order to result in the severing of the paper, while when the blade is relatively `dull, a Vmuch longer movement is required. Thus the scale permits convenient observation of the length of the path of movement of the weight, and accordingly permits convenient ascertainment of a quantitative indication of the cutting ability of the blade. If this operation is repeated a plurality of times, the length of the path of the weight will gradually increase, thus permitting a plurality of readings to be taken soV that a curve can be drawn to indicate the deterioration in cutting ability of the particular blade. t It is obvious that several blades may be compared in this manner to permit convenient determination of their relative cutting abilities or the relative deteriorations thereof.

In the accompanying drawing,

Fig. l is a plan view of apparatus constructed in accordance with this invention;

Fig. 2 is a front elevation of the same, the weight being shown in a dotted line position which it may occupy at th-e end of its path; and l5 Fig. 3 is a side elevation of the apparatus.

Referring to the accompanying drawing, which is illustrative of the invention, the apparatus may comprise a blade support in the form of a pair of blocks I, which are provided with aligned t slots l to receive a cutting blade 2 which is to be tested. Each slot may be dimensioned so that the blade ts tightly therein to preclude relative movement of the blade and its support, or, if desired, thumbscrews Il may be arranged in order to clamp the blade tightly inits support. Extending upwardly from each ofy the blocks l are a pair of spaced uprights 3, which may be arranged at opposite sides of the slot iii but in non-symmetrical relation thereto, so that the beveled cutting edge l2 of the blade may have its cutting portion lying midway between the uprights 3. Secured upon the upper surfaces of the uprights 3 are a pair of guide rails 5 which form a w-eight guide. The weight 20 may include a lower supporting portion 6 of T-shapedfcross section, the depending portion of the member 6 being loosely received between the guide rails 5, and the outstanding flanges thereof being disposed over the rails 5 but spaced therefrom.

A stud 8 may extend upwardly from the miember 6, and a weight element 1 may be provided with a central hole so that it may be disposed in concentric relation to the stud 8 and rest upon the upper surface of the member 5. Thus the weight includes the supporting member 6, the stud 8 and the weight element l. A plurality of elements 'I having diiierent weights may be provided so that these members may be interchangeably disposed on the supporting member 6 as required.

As shown particularly in Fig.` l, therails 5 may be provided with graduatedscales, the zero point of each scale being arranged so that the righthand edge of the weight member 6 (as viewed in Fig. l) may register with the zero graduation when the weight is at the left end of its path. When a device of this character is to be used in testing the cutting ability of a blade, a sheet of material of known characteristics, such as a sheetI of standardized paper stock which has substantially uniform characteristics, may be disposed on the cutting edge of the blade between the same and the lower portion of the support 6. Thus, as is particularly evident from an inspection of Fig. 3, the entire weight of the assembly Y. 20, including the support 6, the stud 8 and the" element l, rests upon the portion; of the paper` Vwhich is being pressed against of the blade.

Since the member 6 has a determined width or extent along the cutting edge of the blade, a determined portion' of the paper is being pressed against the cutting edge. When the parts. are in this position, the edge of the paper l is grasped and moved slowly toward the right, as viewed in Fig. 2, carrying the weight 2B until the paper is severed through, whereupon the weight will rest upon the cutting edge of the blade and the paper mayreadily be removed from the device. There- -upon the reading on the scale which registers with Ythe right-hand edge of the member 6, is

' observed to afford an indication of length of the path of the weight and of the cutting ability of the blade during this particular test.

Y A similar operation may be performed a plurality of times employing a piece or pieces of paper of the same characteristics. Under these Yconditions the extent of the path of the weight Vwill gradually increase as the cutting ability of the blade decreases. Thus a plurality of readings taken following tests in this manner will afford a good indication of the tendency of the cutting ability of the particular blade to deteriorate, it of course being evident that the lengths of the paths of relative movement are inversely proportioned to the cutting ability of the blade.

VIt is evident that a plurality of blades may be in turn disposed in the machine and each blade tested once to afford a quantitative comparison of the cutting abilities ofthe respective blades, or that the several blades may be each tested a number of times so that a determination of the relative durabilities of their cutting edges may be afforded.

When a blade is so dull that the standardized piece of paper stock can not be cut through during a single movement of the weight, the movement may be repeated and the added lengths oi the two movements will afford an approximate quantitative indication of the cuttingY ability of the blade at the particular time. However, under such conditions it is preferable to-substitute a Yheavier' weight element l, thus increasing' the appended claims. f l

Iclaim:y .Y v 1- Apparatus fordetermining the cutting abuthe cutting edgeY ity of a blade, comprising a framework including a supporting portion, a weight-guiding portion, and a `scale portion parallel to the weight-guiding portion, and a weight slidable relative to the guiding portion but arranged so that it may rest VVon the edge of a blade mounted on the supporting portion, whereby a sheet with the Weight resting thereon may be drawn along the edge of the blade until the sheet is severed and the weight Vrests upon the blade edge, whereupon the length of the pathrof the weight may be observed.

2. Apparatus for determining the cutting ability of a blade, comprising a base having a blade supporting portion to hold a blade with its cutting edge uppermost, a weight guide extending parallel to said blade supporting portion, a scale associated with said guide, and a weight movable along said guide and arranged so that it may rest upon a sheet engaging the blade edge or the edge itself, whereby a sheet with the weight resting thereon may be drawn along the edge until the sheet is severed and the weight rests upon the edge, whereupon the extent of the movement of the weight may be determined by observingA its position relative to the scale.

3. Apparatus for determining the cutting ability of a blade, comprising a base arranged to receive and support a blade with its cutting edge disposed uppermost, a weight guide including parallel guide rails, weight means having a portion depending between the guide rails to rest upon the cutting edge or on a sheet engaging said edge, and scale means associated with one of said rails, whereby a sheet with the weight resting thereon may be drawn along the edge until the sheet is severed and the weight rests upon the edge, whereupon the extent of the movement of the weight may be determined by observing its position relative to the scale means.

4. Apparatus for determining the cutting ability of a blade, comprising a base arranged to receive and support a blade with its cutting edge disposed uppermost, a weight guide including parallel guide rails, a weight support having a portion depending between the guide rails to rest upon the cutting edge or on a sheet engaging said edge, and a weight removably mounted on said support, and scale means associated with one of said rails, whereby a sheet with the weight resting thereon may be drawn along the edge until the sheet is severed and the weight rests upon the edge, whereupon the extent of the movement of the weight may be determined by observing its position relative to the scale means.

5. Apparatus for determining the cutting ability of a blade comprising a base having a blade supporting portion to hold a blade with its cutting edge uppermost, a weight guide arranged above said blade supporting portion and a weight movable along said guide and arranged so that it may rest upon a sheet engaging the blade edge or the edge itself, whereby a sheet with the weight resting thereon may be drawn along the edge until the sheet is severed and the weight rests upon the edge whereupon the extent of the movement of the weight may be observed to afford an indication of the cutting ability of the blade.

ERNEST PAUL FLOYD. 

